Neuropeptide Y (hereinafter referred to as NPY) is a peptide which consists of 36 amino acid residues and was isolated from porcine brain in 1982. NPY is widely distributed in the central nervous system and peripheral tissues of humans and animals.
It has been reported that NPY possesses a stimulating activity of food intake, an anti-seizure activity, a learning-promoting activity, an anti-anxiety activity, an anti-stress activity etc. in central nervous system, and it may be pivotally involved in the central nervous system diseases such as depression, Alzheimer's disease and Parkinson's disease. NPY is thought to be associated with the cardiovascular diseases, since it induces a contraction of smooth muscles such as blood vessels or cardiac muscles in the peripheral tissues. Furthermore, NPY is also known to be involved in the metabolic diseases such as obesity, diabetes and hormone abnormalities (Non-patent Document 1). Therefore, an NPY receptor antagonist is expected as a medicine for preventing or treating various diseases involved in the NPY receptor like the above.
Subtypes of Y1, Y2, Y3, Y4, Y5, and Y6 have now been identified as the NPY receptor (Non-patent Document 2). It has been suggested that the Y5 receptor is at least involved in the feeding behavior and its antagonist is expected as an anti-obesity agent (Non-patent Document 3).
Amine derivatives having sulfonyl group and similar structures to compounds of the present invention and exhibiting NPY Y5 receptor antagonistic activity are disclosed in Patent Document 1, 2, 3, 4 and the like. Amide derivatives having sulfonyl group and exhibiting NPY Y5 receptor antagonistic activity are disclosed in Patent Document 5, 8, 9, 10 and 11. Derivatives having sulfonyl group and exhibiting NPY Y5 receptor antagonistic activity are disclosed in Patent Document 12. The structures of these compounds are different from those of the compounds of the present invention.
Furthermore, although compounds having similar structures to compounds of the present invention are disclosed in Patent Document 6, 7, 13, 14 and the like, the activities of their compounds are quite different from those of the compounds of the present invention and these documents do not suggest the present invention.    [Non-patent Document 1] Tends in Pharmacological Sciences, Vol. 15, 153(1994)    [Non-patent Document 2] Trends in Pharmacological Sciences, Vol. 18, 372(1997)    [Non-patent Document 3] Peptides, Vol. 18, 445(1997)    [Patent Document 1] WO01/002379    [Patent Document 2] WO00/064880    [Patent Document 3] WO99/055667    [Patent Document 4] WO00/068197    [Patent Document 5] WO01/037826    [Patent Document 6] WO2006/014482    [Patent Document 7] WO2005/097738    [Patent Document 8] WO97/20823    [Patent Document 9] US2006/293341    [Patent Document 10] WO2007/002126    [Patent Document 11] WO2006/001318    [Patent Document 12] WO2005/080348    [Patent Document 13] US2007/060598    [Patent Document 14] WO2005/121107